As a configuration example of AC motor drive systems, there has been an AC motor drive system in which an inverter that converts DC power into AC power having a voltage value and a frequency different from those of a system power supply to drive an AC motor and a charging/discharging circuit for charging and discharging a power storage device, which stores and discharges the DC power, are connected in parallel, via a smoothing capacitor, to a DC bus on the output side of a converter that converts AC power from the system power supply into DC power.
As an example of such an AC motor drive system, for example, Patent Literature 1 discloses a technology for an AC motor drive system that uses, when regenerative power regenerated from an AC motor via an inverter charges a power storage device via a charging/discharging circuit, a predetermined regeneration-time-current-command-value-integral-component initial value for proportional integral control (PI control) of a charging-current-command-value generating unit in the charging/discharging circuit to cope with regenerative power having a steep regeneration initial value.